1. PHP Workshop ‹#› PHP: The Basics

2. PHP Workshop ‹#› What is it? PHP is a scripting language commonly used on web servers. –Stands for “PHP: Hypertext Preprocessor” –Open source –Embedded code –Comparable with ASP –Multiple operating systems/web servers

3. PHP Workshop ‹#› The PHP Resource www.php.net

4. PHP Workshop ‹#› What can it do? Dynamic generation of web-page content Database interaction Processing of user supplied data Email File handling Text processing Network interaction And more…

5. PHP Workshop ‹#› Fundamentals PHP is embedded within xhtml pages within the tags: The short version of these tags can also be used: Each line of PHP is terminated, like MySQL, with a semi-colon.

6. PHP Workshop ‹#› Hello World! PHP Test Hello World! ’; ?>

7. PHP Workshop ‹#› Preparing to code with PHP

8. PHP Workshop ‹#› Literals.. All strings must be enclosed in single of double quotes: ‘Hello’ or “Hello”. Numbers are not in enclosed in quotes: 1 or 45 or 34.564 Booleans (true/flase) can be written directly as true or false.

9. PHP Workshop ‹#› Comments // This is a comment # This is also a comment /* This is a comment that is spread over multiple lines */ Do not nest multi-line comments // recommended over #

10. PHP Workshop ‹#› Comments <?php // this is a comment echo ‘Hello World!’; /* another multi-line comment */ ?>

11. PHP Workshop ‹#› Displaying Data There are two language constructs available to display data: print() and echo(). They can be used with or without brackets. Note that the data ‘displayed’ by PHP is actually parsed by your browser as HTML. View source to see actual output.

12. PHP Workshop ‹#› Displaying data <?php echo ‘Hello World! ’; echo(‘Hello World! ’); print ‘Hello World! ’; print(‘Hello World! ’); ?>

13. PHP Workshop ‹#› Escaping Characters Some characters are considered ‘special’ Escape these with a backslash \ Special characters will be flagged when they arise, for example a double or single quote belong in this group…

14. PHP Workshop ‹#› Escaping Characters <?php // Claire O’Reilly said “Hello”. echo ‘Claire O\’Reilly ’; echo “said \”Hello\”.”; ?>

15. PHP Workshop ‹#› Variables: What are they? When we work in PHP, we often need a labelled place to store a value (be it a string, number, whatever) so we can use it in multiple places in our script. These labelled ‘places’ are called VARIABLES

16. PHP Workshop ‹#› Variables: Naming $ followed by variable name Case sensitive –$variable differs from $Variable –Stick to lower-case to be sure! Name must started with a letter or an underscore –Followed by any number of letters, numbers and underscores

17. PHP Workshop ‹#› Variables: example <?php $name = ‘Phil’; $age = 23; echo $name; echo ’ is ‘; echo $age; // Phil is 23 ?>

18. PHP Workshop ‹#› Constants Constants (unchangeable variables) can also be defined. Each constant is given a name (note no preceding dollar is applied here). By convention, constant names are usually in UPPERCASE.

19. PHP Workshop ‹#› Constants <?php define(‘NAME’,‘Phil’); define(‘AGE’,23); echo NAME; echo ’ is ‘; echo AGE; // Phil is 23 ?>

20. PHP Workshop ‹#› “ or ‘ ? There is a difference between strings written in single and double quotes. In a double-quoted string any variable names are expanded to their values. In a single-quoted string, no variable expansion takes place.

21. PHP Workshop ‹#› “ or ‘ ? <?php $name = ‘Phil’; $age = 23; echo “$name is $age”; // Phil is 23 ?>

22. PHP Workshop ‹#› “ or ‘ ? <?php $name = ‘Phil’; $age = 23; echo ‘$name is $age’; // $name is $age ?>

23. PHP Workshop ‹#› Review We’ve started PHP.. –Escaping XHTML –Comments –Basic Syntax –Variables –Constants